1. Field of the Invention
The present invention relates to a command queue manager. More particularly, the present invention relates to a method and system for minimizing bus traffic in a video decoder.
2. The Background Art
With the merging of personal computer systems and entertainment systems, digital component video and audio were developed. Typically, this audio and video data are encoded into a compressed program stream for transmission. A stream demultiplexer parses the incoming program stream into audio and video bitstreams. When video frames are ultimately displayed, there must be a decompression of these compressed video bitstreams. A video decoder is used for this decompression, or decoding, process.
According to the MPEG-2 video compression standard, the compression ratio can be as high as 50 to 1. Similarly, decompression expands data up to 50 times. This high data rate, as well as the high video window resolution of MPEG-2 decoding, puts heavy demands on the video system. Moreover, at the present time, a video decoder must accommodate a frame rate of approximately 30 frames per second.
Traditionally, software sends video data to a video decoder implemented entirely in hardware. If the entire decoder is built in hardware, then only a compressed data stream is needed. As a result, a decoder built entirely in hardware is extremely fast. However, the hardwired decoder is inflexible as well as complex, which makes the debugging process extremely difficult. In addition, the hardwired decoder requires numerous gates, resulting in a costly system.
Software can be used to provide greater versatility. However, software is computation intensive, and results in a substantial increase in bus traffic. Accordingly, a need exists for a video decoder which provides greater flexibility than the hardwired decoder while minimizing bus traffic and reducing hardware costs.